.parent {
    width: 500px;
    background-color: #fff;
    padding: 8px;
    border: 1px solid #1b6d85;
}

.child {
    width: 100%;
    background-color: skyblue;
    padding: 8px;
}

.grand {
    width: 100%;
    padding: 8px;
}

.light {
    background-color: #fff;
    color: #000;
    border: 1px solid black;
}

.dark {
    background-color: #000;
    color: #fff;
    border: 3px solid orange;
}